package com.hmdp.utils;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSON;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.hmdp.entity.Shop;
import io.netty.util.internal.StringUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

import static com.hmdp.utils.RedisConstants.*;

@Slf4j
@Component
public class CacheClient {

    public final StringRedisTemplate stringRedisTemplate;

    public CacheClient(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }
//    set
    public void set(String key, Object value, Long time, TimeUnit unit){
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(value),time,unit);
        return;

    }
    public void setWithLogicalExpire(String key,Object value,Long time,TimeUnit unit){
        RedisData redisData=new RedisData();
        redisData.setData(value);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(unit.toSeconds(time)));
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(redisData));

    }
//    工具类读取
    public<R,ID> R queryWithPassThrough(Long time,TimeUnit timeUnit,String keyPrefix, ID id, Class<R> type, Function<ID,R>dbFallback){
        String key=keyPrefix+id;
        String RJson = stringRedisTemplate.opsForValue().get(key);
        if(StrUtil.isNotBlank(RJson)){
            return JSONUtil.toBean(RJson,type);

        }
        if(RJson!=null){
            return null;
        }
        R object=dbFallback.apply(id);
        if(object==null){
            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.SECONDS);
            return null;
        }
        this.set(key,object,time,timeUnit);
        return object;

    }


    private static final ExecutorService CACHE_REBUILD_EXECUTOR= Executors.newFixedThreadPool(10);
    public<ID,R>  R queryWithLogicalExpire(Long time,TimeUnit timeUnit,String keyPrefix, ID id, Class<R> type, Function<ID,R>dbFallback){
        String key= CACHE_SHOP_KEY+id;
        String shopJson=stringRedisTemplate.opsForValue().get(key);
        if(StrUtil.isBlank(shopJson)){
            return null;
        }

        RedisData redisData=JSONUtil.toBean(shopJson, RedisData.class);
        R shop=JSONUtil.toBean((JSONObject) redisData.getData(),type);
        LocalDateTime expireTime=redisData.getExpireTime();
        if(expireTime.isAfter(LocalDateTime.now())){
            return shop;
        }
        String lockkey="Lock:"+key;
        boolean isLock=trylock(key);
        if(isLock){
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    R r1 = dbFallback.apply(id);
                    setWithLogicalExpire(key,r1,time,timeUnit);
                }catch (Exception e){
                    throw new RuntimeException();
                }finally {
                    unlock(lockkey);
                }
            });
        }
        return shop;
    }
    private boolean trylock(String key){
        Boolean b = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(b);
    }
    private void unlock(String key){
        stringRedisTemplate.delete(key);
    }


}
